Trammel-point



H. V. SOUDE'RS.

TRAMMEL POINT.

APPLICATION FILED MAY 10. 1919.

Patented Sept. '7, 1920.

WITNESSES WW4, I

ATTORN Ev NET STATES 'HERBERT V. SOUDERS, 0F WILMINGTON, CALIFORNIA.

IRAMMEL-rom'r. 5

Specification of Letters Patent. Patented Sept, 1920,

Application filed May 10, 1919. Seriallio. 296,163.-

This invention has reierencerto improvements in tranimel points, and its object is to provide 'trammel points having a greater extent of usefulness and more flexibility of adjustment than is provided for by the ordinary trammel points.

In accordance with the invention, two points, somewhat difierent in structure, are provided, and these points, like points of ordinary construction,are designed to be secured upon a trammel bar so that the points are used in conjunction. One point is designed to remain in fixed position upon the bar while the other point has a range of adjustment with relation to the first-named point, and the structure is such that adjustments may be very accurately made for distances between two points or for diameters. The invention provides-iorcoarse and fine adjustments with the fine adjustment of a character .to hold its position, but provision is made for locking the fine adjustment in adjusted positions to relieve the adjusting means from strain, such adjusting means being of a relatively delicate nature due to micrometric conditions. The invention also contemplates the employment of certain structures which contribute to the accuracy of measurement and ease of operation.

The invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawing forming part of this specification, with the understanding, however, that the invention 1s not 'confined to any strict conformity with the showing of the drawing, but may be changed and modified so long-as such changes and modifications mark no material departure from the salient features of the invention as expressed in'the appended claims.

In the drawing Figure 1 is an elevation of a trammel bar with the trammel points of the invention mounted thereon.

Fig. 2 is a section on the line 2'2 of Fig. '1, the bar being omitted."v

Fig. 3 is a section on the line 33 of Fig. 2.

Fig. 1 is a section on theline 4-4. of Fig. 1, the bar being omitted.

Referring to the drawing, there is shown a bar 1 which may be of ordinary type and of suitable length and cross section. Mounted on the bar are two 'trammel heads 'A'and;

B 'respectively, the headA being provided with certain adjusting mechanism and the head B being free from such mcchanism. The head- A has a voke portionQof a length greater than the width of the bar 1 and provided at the ends with arms 3 and 1 respectively, n opposed relation. The arm 3 is tapped for the passage of a clamp screw 5 having at one: end, constituting the outer.

end, a' manipulating portion 6 which may be in the form of a peripherally milled wheel,

and at the other end, that toward the end 4:, carrying a swivel disk. 7 This provides for clamping the head A onto-the bar 1 by seating one edge of the bar against the arm 4 and forcing the disk 7, against the other edge of the bar by means of the screwv 5.

Formed on that face of the head A remote fromthe clamping portion ofthe headis acylindrical shell 8 which maybe located about midway between the ends of the head, which latter is longer crosswise of the bar 1 than lengthwise thereof. Extending from one side oi'the shell 8 towardtheadjacent end of the head A is a strengthening web 9 and between the other side of the shell 8 and the corresponding end of the head A are crossed webs or enlargements10, 11 respectively. The enlargement 10' is tangential to the shell ,Swhilethe enlargement 11 is perpendicular to the enlargement 10. The

enlargement 10 is provided with a longitudinal bore 12 entering one end of the enlargement and intersecting the shell 8 tangential to the interior thereof. The. en-, largement 11 is-tapped lengthwise for the reception ofa set screw 13. I

Seated in the shell" 8 ie a .block 14 of greater thickness than the depth ofthe shell and provided with a circular series of worm teeth 15? constituting a circular. worm gear. Extending 111130 the bore 12 is a screw stem 15 having a manipulating wheel 16 at the outerend beyond the enlargement 10, and

within the bore; 12, where intersecting the shellS, the stem 15 is formed with a worm l6? engaging the worm gear 15 so that on turning the screw stem l5 -the worm gear may be rotated. The block l i is counterbored on the inner face, as shown at l7, and

.wheel 20 at one end and at the other en screw-threaded, as shown at 21, and there entering a suitably threaded passage through the boss 18 so that the screw 19 serves as a clamp screw for holding the block 14 against rotation when desired. Projecting tangentially from the block 14 is an arm 22, and extending lengthwise through the arm and tangentially through the block 14 is a passage 23 through which there passes a rod 24 having one end 25 pointed to serve as a trammel point while the other end 26 of the rod is bent angularly and pointed to serve as a caliper point. The rod 24 is held to the block 14 and arm 22 by a set screw 27 having a manipulating wheel or head 27.

The trammel member or head B has a yoke portion'28 similar to the yoke portion 2 of the head A and at the ends of the B, which, like the head A, is longer crosswise of the bar'" 1 than lengthwise thereof, is a web or enlargement 34 increasing progressively in extent ofprojection from one end of-the head toward the other. Extending through the web 34 lengthwise of the latter and entering the web at a distance from its thin end is a bore 35 parallel with the yoke 28 and traversed by a rod 36 having one end 37 pointed and the otherjend 38 bent at an angle and pointed. The rods 24 and 36 are alike and constitute the trammel points of the two heads A and B. The web 34' at its thick end is traversed bya set screw 39, like the setscrew 26, and servinga like purpose. 9

The head B is clamped fast to the bar 1 at a desired position and is so arranged that the head B is toward that'end of the bar to the left of the user. The head A is clamped to the bar to the right ofthe head '13 at such distance from the hea'd 'B as conditions may demand. The point 37 of the;

rod 36 is placed upon a part of thework representing one end of the portion tobe measured and the point 25 is placed as near as convenient to the other limit of the space to bemeasured; Then by setting the screw 19 so as to yieldingl hold the block.14, the screw 15 is manipu ated to turn the block 14 about its axis of rotation by minute dis tances made possible by the worm gearing. When the proper position is reached by the or other purposes.

ments.

point 25 the screw 19 may be tightened, thus holding the measurement for transfer The adjustment of the trammel rod 24 is exceedingly delicate, depending upon the sense of touch and the extreme minuteness of the possible move-' curacy of measurement and transfer of measurement is obtainable with the invention which is not possible with trammel points as ordinarily constructed.

By loosening the screws 27 and 39 the rods 24 and 36 may be reversed and reclamped, thus permitting the use of the caliper points 26 and 38 for calipering purposes. For some measurements one only of the trammel rods need be reversed.

The trammel head A is arranged so that the fine adjustment of the rod 24 can be performed by the right hand and the clamping of the rod may likewise-be performed by the right hand, thus avoiding the necessity of removing the trammel structure from the work during adjustment.

The trammel structure is intended to be an instrument of precision and the precision V of operation is maintained by the set screw 13, allowing all lost motion of the worm actuating means to be taken up as needed. In fact, the set screw 13 has several functions. It holds the worm screw 15 in position, pre venting longitudinal movement thereof when the worm screw is manipulated to rotate the block 14 in either direction. It

I takes up all wear which occurs between the worm screw 15 and the worm gear 15 and it also compensates for wearwhich occurs on the thrust in either direction. In order to provide for these functions the set screw 13 has a taper end set in a correspondingly shaped groove in the stem of the worm screw 15. The Web 9 and enlargements 10 and 11' of the head A and the web 34 of the head B' contribute materially to the stiffness'of these, parts, not only rendering them more accurate in taking or transferring measurements, but avoiding distortion of the points under conditions of use.

In both heads A and B the passagestraversed-by the trammel rods are elongated so that these rods have correspondingly long supports and are therefore much more rigid than is customary.

What is claimed is 1. A trammel structure comprising two heads each having on one face a clamp for engaging a trammel bar'and on the opposite face means for holding a clamping trammel point thereto, one of the heads having the holding means for the trammel point rotatable about an axis perpendicular to the face of the head, and also including means Because of these features an acfor clamping the rotatable part in adjusted head, a worm gear mounted for rotation thereon, a worm engaging the worm gear, a carrier fast on the worm gear and having a passage therethrough for a trammel point, and means on the carrier for clamping a trammel point in adjusted positions in the passage and arranged eccentrically to the axis of rotation of the worm gear.

3. In a trammel structure, a trammel head, a rotatable block mounted thereon and provided with a worm gear, an arm on the block in tangential relation to the axis of rotation of the block, said block and arm having a passage therethrough tangential to the axis of rotation of the block, a worm engaging the Worm gear and provided with means for its manipulation, and a housing for the worm gear and worm.

4:. In a trammel structure, a trammel head having a shell projecting from one face, a rotatable block mounted in and projecting from the shell and provided with a circular series of worm teeth on that portion within the shell, said block also having an enlargement with a bore tangential to the shell and opening therein, a worm housed in the bore and provided with manipulating means exterior thereto, and carrying means for a trammel point on said block.

5. In a trammel structure, a trammel head having a shell projecting from one face, a rotatable block mounted in and projecting from the shell and provided with a circular series of worm teeth on that portion within the shell, said block also having an enlargement with a bore tangential to the shell and opening therein, a worm housed in the bore and provided with manipulating means exterior thereto, and carrying means for a trammel point on said block, the head also being provided with an interiorly threaded enlargement perpendicular to the first-named enlargement and provided with a set screw for engaging the worm in the first-named enlargement to hold it therein.

6. In a trammel structure, a trammel head having a shell projecting from one face, a

rotatable block mounted in and projecting from the shell and provided with a circular series of worm teeth on that portion within the shell, said block also having an enlargement with a bore tangential to the shell and opening therein, a worm housed in the bore and provided with manipulating means exterior thereto, and carrying means for a trammel point on said block, the head also being provided with an interiorly threaded enlargement perpendicular to the first-named enlargement and provided with a set screw for engaging the worm in the first-named enlargement to hold it therein, and said block being provided with a clamp screw traversing the block and engaging the head whereby to hold the block in set position.

7 In a trammel structure, a trammel head for application to a bar, said trammel head being provided with a carrier for a trammel point andprovided with means for rotating the carrier and point throughout a full circle.

8. In a trammel structure, a trammel head for application to a bar, said trammel head being provided with a carrier for a trammel point and provided with means for rotating the carrier and point throughout a full circle, and said rotatable carrier, hav ing clamping means associated therewith for holding it in any desired adjusted position about its axis of rotation.v

9. In a trammel structure, a trammel head for application to a bar, said trammel head being provided with a carrier for a trammel point and provided with means for rotating the carrier and point comprising a circular worm gear, a worm screw engaging the worm gear and provided'with a circumferential groove of taper cross section, and a set screw with a taper point entering the groove.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature.

HERBERT V. SOUDERS. Witnesses:

STEPHEN MCCARTHY, T. S. CARY. 

